SUMMARY?CORE B: CLINICAL CORE. The Clinical Core supports the Harvard Aging Brain Study (HABS) Program Project Grant (PPG) by evaluating and retaining a sample of older individuals (ages 60 to 90), all of whom joined HABS when they were clinically normal with annual comprehensive clinical and neuropsychological assessments. To date, there are 277 continuing participants from diverse ethnic and socioeconomic backgrounds with a 96% retention rate of the Baseline cohort thus far. While attrition is inevitable in a cohort of elderly individuals, the goal will be to retain at least 250 subjects through Visit 7 imaging procedures (Aim 1). The Clinical Core will also work closely with Core D: Analytic Core to monitor attrition in the overall Project, as well as monitor and adjust recruiting for the composition of the proposed sub- study of subjects required for the ADVANCED Imaging Cohort in Projects 1 and 3 and the iPad cohort in Project 4. The Clinical Core will schedule and assess all participants on an annual basis using well- established measures of cognition, mood, social engagement, physical exercise, olfaction, quality of life, activities of daily living and subjective cognitive concerns as well as assist with training on the iPad for novel tests administered in the home environment in Project 4 (Aim 2). The Core will coordinate the scheduling of all subjects' imaging procedures with Core C: Imaging Core, for subjects participating in Projects 1, 3 and 4 (Aim 3). The Clinical Core will collect biological fluid samples for biomarker and genetic studies in coordination with the Harvard NeuroDiscovery Center (HNDC) Biomarkers Study (Aim 4) and facilitate discussion of brain donation and coordination of successful autopsy completion with the Massachusetts Alzheimer Disease Research Center's Neuropathology Core for Project 2 (Aim 5). The Clinical Core will also provide clinical and neuropsychological expertise to the Projects and interact cooperatively with all components of the HABS PPG (Aim 6). The Clinical Core is comprised of a strong and seasoned group of multidisciplinary clinical investigators, with specialized training in neurology, neuropsychology and geriatric psychiatry and includes a dedicated clinical research staff that will facilitate the careful characterization and longitudinal follow-up of the HABS cohort. The Clinical Core and the overall HABS PPG seek to improve our understanding of the aging brain, and the role of amyloid and tau pathologies in predicting the development of imminent cognitive decline. This Core will retain and longitudinally evaluate an ethnically and socioeconomically diverse group of older individuals in order to better understand the transition from changes associated with normal aging to the earliest manifestations of Alzheimer's disease.